﻿using System.IO;
using System.Threading;

namespace Vanara.PInvoke;

public static partial class Kernel32
{
	/// <summary>
	/// Starts the asynchronous operation of sending a control code directly to a specified device driver, causing the corresponding
	/// device to perform the corresponding operation.
	/// </summary>
	/// <typeparam name="TIn">The type of the <paramref name="inVal"/>.</typeparam>
	/// <typeparam name="TOut">The type of the <paramref name="outVal"/>.</typeparam>
	/// <param name="hDevice">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="dwIoControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <param name="inVal">
	/// A pointer to the input buffer that contains the data required to perform the operation. The format of this data depends on the
	/// value of the dwIoControlCode parameter.
	/// <para>This parameter can be NULL if dwIoControlCode specifies an operation that does not require input data.</para>
	/// </param>
	/// <param name="outVal">
	/// A pointer to the output buffer that is to receive the data returned by the operation. The format of this data depends on the
	/// value of the dwIoControlCode parameter.
	/// <para>This parameter can be NULL if dwIoControlCode specifies an operation that does not return data.</para>
	/// </param>
	/// <param name="userCallback">An AsyncCallback delegate that references the method to invoke when the operation is complete.</param>
	/// <returns>An IAsyncResult instance that references the asynchronous request.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static IAsyncResult BeginDeviceIoControl<TIn, TOut>(HFILE hDevice, uint dwIoControlCode, TIn? inVal, TOut? outVal, AsyncCallback userCallback) where TIn : struct where TOut : struct
	{
		var buffer = Pack(inVal, outVal);
		return BeginDeviceIoControl<TIn, TOut>(hDevice, dwIoControlCode, buffer, userCallback, null);
	}

	/// <summary>
	/// Starts the asynchronous operation of sending a control code directly to a specified device driver, causing the corresponding
	/// device to perform the corresponding operation.
	/// </summary>
	/// <param name="hDevice">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="dwIoControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <param name="inputBuffer">The input buffer required to perform the operation. Can be null if unnecessary.</param>
	/// <param name="outputBuffer">The output buffer that is to receive the data returned by the operation. Can be null if unnecessary.</param>
	/// <param name="userCallback">An AsyncCallback delegate that references the method to invoke when the operation is complete.</param>
	/// <returns>An IAsyncResult instance that references the asynchronous request.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static IAsyncResult BeginDeviceIoControl(HFILE hDevice, uint dwIoControlCode, byte[] inputBuffer, byte[] outputBuffer, AsyncCallback userCallback)
	{
		var buffer = Pack(inputBuffer, outputBuffer);
		return BeginDeviceIoControl(hDevice, dwIoControlCode, buffer, userCallback, null);
	}

	/// <summary>
	/// <para>
	/// Cancels all pending input and output (I/O) operations that are issued by the calling thread for the specified file. The function
	/// does not cancel I/O operations that other threads issue for a file handle.
	/// </para>
	/// <para>To cancel I/O operations from another thread, use the <c>CancelIoEx</c> function.</para>
	/// </summary>
	/// <param name="hFile">
	/// <para>A handle to the file.</para>
	/// <para>The function cancels all pending I/O operations for this file handle.</para>
	/// </param>
	/// <returns>
	/// <para>
	/// If the function succeeds, the return value is nonzero. The cancel operation for all pending I/O operations issued by the calling
	/// thread for the specified file handle was successfully requested. The thread can use the <c>GetOverlappedResult</c> function to
	/// determine when the I/O operations themselves have been completed.
	/// </para>
	/// <para>If the function fails, the return value is zero (0). To get extended error information, call the <c>GetLastError</c> function.</para>
	/// </returns>
	// BOOL WINAPI CancelIo( _In_ HANDLE hFile);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363791(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "aa363791")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern bool CancelIo([In, AddAsMember] HFILE hFile);

	/// <summary>
	/// Marks any outstanding I/O operations for the specified file handle. The function only cancels I/O operations in the current
	/// process, regardless of which thread created the I/O operation.
	/// </summary>
	/// <param name="hFile">A handle to the file.</param>
	/// <param name="lpOverlapped">
	/// <para>A pointer to an <c>OVERLAPPED</c> data structure that contains the data used for asynchronous I/O.</para>
	/// <para>If this parameter is <c>NULL</c>, all I/O requests for the hFile parameter are canceled.</para>
	/// <para>
	/// If this parameter is not <c>NULL</c>, only those specific I/O requests that were issued for the file with the specified
	/// lpOverlapped overlapped structure are marked as canceled, meaning that you can cancel one or more requests, while the
	/// <c>CancelIo</c> function cancels all outstanding requests on a file handle.
	/// </para>
	/// </param>
	/// <returns>
	/// <para>
	/// If the function succeeds, the return value is nonzero. The cancel operation for all pending I/O operations issued by the calling
	/// process for the specified file handle was successfully requested. The application must not free or reuse the <c>OVERLAPPED</c>
	/// structure associated with the canceled I/O operations until they have completed. The thread can use the
	/// <c>GetOverlappedResult</c> function to determine when the I/O operations themselves have been completed.
	/// </para>
	/// <para>If the function fails, the return value is 0 (zero). To get extended error information, call the <c>GetLastError</c> function.</para>
	/// <para>If this function cannot find a request to cancel, the return value is 0 (zero), and <c>GetLastError</c> returns <c>ERROR_NOT_FOUND</c>.</para>
	/// </returns>
	// BOOL WINAPI CancelIoEx( _In_ HANDLE hFile, _In_opt_ LPOVERLAPPED lpOverlapped);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363792(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "aa363792")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern unsafe bool CancelIoEx([In] HFILE hFile, [In, Optional] NativeOverlapped* lpOverlapped);

	/// <summary>Marks pending synchronous I/O operations that are issued by the specified thread as canceled.</summary>
	/// <param name="hThread">A handle to the thread.</param>
	/// <returns>
	/// <para>If the function succeeds, the return value is nonzero.</para>
	/// <para>If the function fails, the return value is 0 (zero). To get extended error information, call the <c>GetLastError</c> function.</para>
	/// <para>If this function cannot find a request to cancel, the return value is 0 (zero), and <c>GetLastError</c> returns <c>ERROR_NOT_FOUND</c>.</para>
	/// </returns>
	// BOOL WINAPI CancelSynchronousIo( _In_ HANDLE hThread); https://msdn.microsoft.com/en-us/library/windows/desktop/aa363794(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "aa363794")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern unsafe bool CancelSynchronousIo([In, AddAsMember] HTHREAD hThread);

	/// <summary>
	/// <para>
	/// Creates an input/output (I/O) completion port and associates it with a specified file handle, or creates an I/O completion port
	/// that is not yet associated with a file handle, allowing association at a later time.
	/// </para>
	/// <para>
	/// Associating an instance of an opened file handle with an I/O completion port allows a process to receive notification of the
	/// completion of asynchronous I/O operations involving that file handle.
	/// </para>
	/// </summary>
	/// <param name="FileHandle">
	/// <para>An open file handle or <c>INVALID_HANDLE_VALUE</c>.</para>
	/// <para>The handle must be to an object that supports overlapped I/O.</para>
	/// <para>
	/// If a handle is provided, it has to have been opened for overlapped I/O completion. For example, you must specify the
	/// <c>FILE_FLAG_OVERLAPPED</c> flag when using the <c>CreateFile</c> function to obtain the handle.
	/// </para>
	/// <para>
	/// If <c>INVALID_HANDLE_VALUE</c> is specified, the function creates an I/O completion port without associating it with a file
	/// handle. In this case, the ExistingCompletionPort parameter must be <c>NULL</c> and the CompletionKey parameter is ignored.
	/// </para>
	/// </param>
	/// <param name="ExistingCompletionPort">
	/// <para>A handle to an existing I/O completion port or <c>NULL</c>.</para>
	/// <para>
	/// If this parameter specifies an existing I/O completion port, the function associates it with the handle specified by the
	/// FileHandle parameter. The function returns the handle of the existing I/O completion port if successful; it does not create a new
	/// I/O completion port.
	/// </para>
	/// <para>
	/// If this parameter is <c>NULL</c>, the function creates a new I/O completion port and, if the FileHandle parameter is valid,
	/// associates it with the new I/O completion port. Otherwise no file handle association occurs. The function returns the handle to
	/// the new I/O completion port if successful.
	/// </para>
	/// </param>
	/// <param name="CompletionKey">
	/// The per-handle user-defined completion key that is included in every I/O completion packet for the specified file handle. For
	/// more information, see the Remarks section.
	/// </param>
	/// <param name="NumberOfConcurrentThreads">
	/// <para>
	/// The maximum number of threads that the operating system can allow to concurrently process I/O completion packets for the I/O
	/// completion port. This parameter is ignored if the ExistingCompletionPort parameter is not <c>NULL</c>.
	/// </para>
	/// <para>If this parameter is zero, the system allows as many concurrently running threads as there are processors in the system.</para>
	/// </param>
	/// <returns>
	/// <para>If the function succeeds, the return value is the handle to an I/O completion port:</para>
	/// <para>
	/// If the function fails, the return value is <c>NULL</c>. To get extended error information, call the <c>GetLastError</c> function.
	/// </para>
	/// </returns>
	/// <remarks>
	/// <para>
	/// The I/O system can be instructed to send I/O completion notification packets to I/O completion ports, where they are queued. The
	/// <c>CreateIoCompletionPort</c> function provides this functionality.
	/// </para>
	/// <para>
	/// An I/O completion port and its handle are associated with the process that created it and is not sharable between processes.
	/// However, a single handle is sharable between threads in the same process.
	/// </para>
	/// <para><c>CreateIoCompletionPort</c> can be used in three distinct modes:</para>
	/// <list type="bullet">
	/// <item>
	/// <term>Create only an I/O completion port without associating it with a file handle.</term>
	/// </item>
	/// <item>
	/// <term>Associate an existing I/O completion port with a file handle.</term>
	/// </item>
	/// <item>
	/// <term>Perform both creation and association in a single call.</term>
	/// </item>
	/// </list>
	/// <para>
	/// To create an I/O completion port without associating it, set the FileHandle parameter to <c>INVALID_HANDLE_VALUE</c>, the
	/// ExistingCompletionPort parameter to <c>NULL</c>, and the CompletionKey parameter to zero (which is ignored in this case). Set the
	/// NumberOfConcurrentThreads parameter to the desired concurrency value for the new I/O completion port, or zero for the default
	/// (the number of processors in the system).
	/// </para>
	/// <para>
	/// The handle passed in the FileHandle parameter can be any handle that supports overlapped I/O. Most commonly, this is a handle
	/// opened by the <c>CreateFile</c> function using the <c>FILE_FLAG_OVERLAPPED</c> flag (for example, files, mail slots, and pipes).
	/// Objects created by other functions such as <c>socket</c> can also be associated with an I/O completion port. For an example using
	/// sockets, see <c>AcceptEx</c>. A handle can be associated with only one I/O completion port, and after the association is made,
	/// the handle remains associated with that I/O completion port until it is closed.
	/// </para>
	/// <para>For more information on I/O completion port theory, usage, and associated functions, see I/O Completion Ports.</para>
	/// <para>
	/// Multiple file handles can be associated with a single I/O completion port by calling <c>CreateIoCompletionPort</c> multiple times
	/// with the same I/O completion port handle in the ExistingCompletionPort parameter and a different file handle in the FileHandle
	/// parameter each time.
	/// </para>
	/// <para>
	/// Use the CompletionKey parameter to help your application track which I/O operations have completed. This value is not used by
	/// <c>CreateIoCompletionPort</c> for functional control; rather, it is attached to the file handle specified in the FileHandle
	/// parameter at the time of association with an I/O completion port. This completion key should be unique for each file handle, and
	/// it accompanies the file handle throughout the internal completion queuing process. It is returned in the
	/// <c>GetQueuedCompletionStatus</c> function call when a completion packet arrives. The CompletionKey parameter is also used by the
	/// <c>PostQueuedCompletionStatus</c> function to queue your own special-purpose completion packets.
	/// </para>
	/// <para>
	/// After an instance of an open handle is associated with an I/O completion port, it cannot be used in the <c>ReadFileEx</c> or
	/// <c>WriteFileEx</c> function because these functions have their own asynchronous I/O mechanisms.
	/// </para>
	/// <para>
	/// It is best not to share a file handle associated with an I/O completion port by using either handle inheritance or a call to the
	/// <c>DuplicateHandle</c> function. Operations performed with such duplicate handles generate completion notifications. Careful
	/// consideration is advised.
	/// </para>
	/// <para>
	/// The I/O completion port handle and every file handle associated with that particular I/O completion port are known as references
	/// to the I/O completion port. The I/O completion port is released when there are no more references to it. Therefore, all of these
	/// handles must be properly closed to release the I/O completion port and its associated system resources. After these conditions
	/// are satisfied, close the I/O completion port handle by calling the <c>CloseHandle</c> function.
	/// </para>
	/// <para>In Windows 8 and Windows Server 2012, this function is supported by the following technologies.</para>
	/// <list type="table">
	/// <listheader>
	/// <term>Technology</term>
	/// <term>Supported</term>
	/// </listheader>
	/// <item>
	/// <term>Server Message Block (SMB) 3.0 protocol</term>
	/// <term>Yes</term>
	/// </item>
	/// <item>
	/// <term>SMB 3.0 Transparent Failover (TFO)</term>
	/// <term>Yes</term>
	/// </item>
	/// <item>
	/// <term>SMB 3.0 with Scale-out File Shares (SO)</term>
	/// <term>Yes</term>
	/// </item>
	/// <item>
	/// <term>Cluster Shared Volume File System (CsvFS)</term>
	/// <term>Yes</term>
	/// </item>
	/// <item>
	/// <term>Resilient File System (ReFS)</term>
	/// <term>Yes</term>
	/// </item>
	/// </list>
	/// </remarks>
	// https://docs.microsoft.com/en-us/windows/desktop/FileIO/createiocompletionport
	// HANDLE WINAPI CreateIoCompletionPort( _In_ HANDLE FileHandle, _In_opt_ HANDLE ExistingCompletionPort, _In_ ULONG_PTR CompletionKey, _In_ DWORD NumberOfConcurrentThreads );
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "40cb47fc-7b15-47f6-bee2-2611d4686053")]
	public static extern HANDLE CreateIoCompletionPort([In] HANDLE FileHandle, [In, Optional] HANDLE ExistingCompletionPort,
		[In, Optional] IntPtr CompletionKey, uint NumberOfConcurrentThreads);

	/// <summary>This macro is used to create a unique system I/O control code (IOCTL).</summary>
	/// <param name="deviceType">
	/// Defines the type of device for the given IOCTL. This parameter can be no bigger then a WORD value. The values used by Microsoft
	/// are in the range 0-32767 and the values 32768-65535 are reserved for use by OEMs and IHVs.
	/// </param>
	/// <param name="function">
	/// Defines an action within the device category. That function codes 0-2047 are reserved for Microsoft, and 2048-4095 are reserved
	/// for OEMs and IHVs. The function code can be no larger then 4095.
	/// </param>
	/// <param name="method">
	/// Defines the method codes for how buffers are passed for I/O and file system controls. The following list shows the possible
	/// values for this parameter:
	/// <list type="bullet">
	/// <item>
	/// <description>METHOD_BUFFERED</description>
	/// </item>
	/// <item>
	/// <description>METHOD_IN_DIRECT</description>
	/// </item>
	/// <item>
	/// <description>METHOD_OUT_DIRECT</description>
	/// </item>
	/// <item>
	/// <description>METHOD_NEITHER</description>
	/// </item>
	/// </list>
	/// <para>
	/// This field is ignored under Windows CE and you should always use the METHOD_BUFFERED value unless compatibility with the desktop
	/// is required using a different Method value.
	/// </para>
	/// </param>
	/// <param name="access">
	/// Defines the access check value for any access. The following table shows the possible flags for this parameter. The
	/// FILE_ACCESS_ANY is generally the correct value.
	/// <list type="table">
	/// <listheader>
	/// <term>Flag</term>
	/// <term>Description</term>
	/// </listheader>
	/// <item>
	/// <term>FILE_ANY_ACCESS</term>
	/// <term>Request all access.</term>
	/// </item>
	/// <item>
	/// <term>FILE_READ_ACCESS</term>
	/// <term>Request read access. Can be used with FILE_WRITE_ACCESS.</term>
	/// </item>
	/// <item>
	/// <term>FILE_WRITE_ACCESS</term>
	/// <term>Request write access. Can be used with FILE_READ_ACCESS.</term>
	/// </item>
	/// </list>
	/// </param>
	/// <returns>The resulting I/O control code.</returns>
	/// <exception cref="ArgumentOutOfRangeException">function</exception>
	public static uint CTL_CODE(ushort deviceType, ushort function, byte method, byte access)
	{
		if (function > 0xfff)
			throw new ArgumentOutOfRangeException(nameof(function));
		return (uint)((deviceType << 0x10) | (access << 14) | (function << 2) | method);
	}

	/// <summary>This macro is used to create a unique system I/O control code (IOCTL).</summary>
	/// <param name="deviceType">
	/// Defines the type of device for the given IOCTL. This parameter can be no bigger then a WORD value. The values used by Microsoft
	/// are in the range 0-32767 and the values 32768-65535 are reserved for use by OEMs and IHVs.
	/// </param>
	/// <param name="function">
	/// Defines an action within the device category. That function codes 0-2047 are reserved for Microsoft, and 2048-4095 are reserved
	/// for OEMs and IHVs. The function code can be no larger then 4095.
	/// </param>
	/// <param name="method">
	/// Defines the method codes for how buffers are passed for I/O and file system controls.
	/// <para>
	/// This field is ignored under Windows CE and you should always use the METHOD_BUFFERED value unless compatibility with the desktop
	/// is required using a different Method value.
	/// </para>
	/// </param>
	/// <param name="access">Defines the access check value for any access.</param>
	/// <returns>The resulting I/O control code.</returns>
	public static uint CTL_CODE(DEVICE_TYPE deviceType, ushort function, IOMethod method, IOAccess access) =>
		CTL_CODE((ushort)deviceType, function, (byte)method, (byte)access);

	/// <summary>
	/// Sends a control code directly to a specified device driver, causing the corresponding device to perform the corresponding operation.
	/// </summary>
	/// <param name="hDevice">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="dwIoControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <param name="lpInBuffer">
	/// A pointer to the input buffer that contains the data required to perform the operation. The format of this data depends on the
	/// value of the dwIoControlCode parameter.
	/// <para>This parameter can be NULL if dwIoControlCode specifies an operation that does not require input data.</para>
	/// </param>
	/// <param name="nInBufferSize">The size of the input buffer, in bytes.</param>
	/// <param name="lpOutBuffer">
	/// A pointer to the output buffer that is to receive the data returned by the operation. The format of this data depends on the
	/// value of the dwIoControlCode parameter.
	/// <para>This parameter can be NULL if dwIoControlCode specifies an operation that does not return data.</para>
	/// </param>
	/// <param name="nOutBufferSize">The size of the output buffer, in bytes.</param>
	/// <param name="lpBytesReturned">
	/// A pointer to a variable that receives the size of the data stored in the output buffer, in bytes.
	/// <para>
	/// If the output buffer is too small to receive any data, the call fails, GetLastError returns ERROR_INSUFFICIENT_BUFFER, and
	/// lpBytesReturned is zero.
	/// </para>
	/// <para>
	/// If the output buffer is too small to hold all of the data but can hold some entries, some drivers will return as much data as
	/// fits. In this case, the call fails, GetLastError returns ERROR_MORE_DATA, and lpBytesReturned indicates the amount of data
	/// received. Your application should call DeviceIoControl again with the same operation, specifying a new starting point.
	/// </para>
	/// <para>
	/// If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation returns no output data and lpOutBuffer is NULL,
	/// DeviceIoControl makes use of lpBytesReturned. After such an operation, the value of lpBytesReturned is meaningless.
	/// </para>
	/// <para>
	/// If lpOverlapped is not NULL, lpBytesReturned can be NULL. If this parameter is not NULL and the operation returns data,
	/// lpBytesReturned is meaningless until the overlapped operation has completed. To retrieve the number of bytes returned, call
	/// GetOverlappedResult. If hDevice is associated with an I/O completion port, you can retrieve the number of bytes returned by
	/// calling GetQueuedCompletionStatus.
	/// </para>
	/// </param>
	/// <param name="lpOverlapped">
	/// A pointer to an OVERLAPPED structure.
	/// <para>If hDevice was opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.</para>
	/// <para>
	/// If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, the operation is performed as an overlapped (asynchronous) operation.
	/// In this case, lpOverlapped must point to a valid OVERLAPPED structure that contains a handle to an event object. Otherwise, the
	/// function fails in unpredictable ways.
	/// </para>
	/// <para>
	/// For overlapped operations, DeviceIoControl returns immediately, and the event object is signaled when the operation has been
	/// completed. Otherwise, the function does not return until the operation has been completed or an error occurs.
	/// </para>
	/// </param>
	/// <returns>
	/// If the operation completes successfully, the return value is nonzero.
	/// <para>If the operation fails or is pending, the return value is zero. To get extended error information, call GetLastError.</para>
	/// </returns>
	/// <remarks>
	/// <para>
	/// To retrieve a handle to the device, you must call the CreateFile function with either the name of a device or the name of the
	/// driver associated with a device. To specify a device name, use the following format:
	/// </para>
	/// <para>\\.\DeviceName</para>
	/// <para>
	/// DeviceIoControl can accept a handle to a specific device. For example, to open a handle to the logical drive
	/// A: with CreateFile, specify \\.\a:. Alternatively, you can use the names \\.\PhysicalDrive0, \\.\PhysicalDrive1, and so on, to
	/// open handles to the physical drives on a system.
	/// </para>
	/// <para>
	/// You should specify the FILE_SHARE_READ and FILE_SHARE_WRITE access flags when calling CreateFile to open a handle to a device
	/// driver. However, when you open a communications resource, such as a serial port, you must specify exclusive access. Use the other
	/// CreateFile parameters as follows when opening a device handle:
	/// </para>
	/// <list type="bullet">
	/// <item>
	/// <description>The fdwCreate parameter must specify OPEN_EXISTING.</description>
	/// </item>
	/// <item>
	/// <description>The hTemplateFile parameter must be NULL.</description>
	/// </item>
	/// <item>
	/// <description>
	/// The fdwAttrsAndFlags parameter can specify FILE_FLAG_OVERLAPPED to indicate that the returned handle can be used in overlapped
	/// (asynchronous) I/O operations.
	/// </description>
	/// </item>
	/// </list>
	/// </remarks>
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static extern bool DeviceIoControl(HFILE hDevice, uint dwIoControlCode, [In, Optional] IntPtr lpInBuffer,
		[In, Optional] uint nInBufferSize, [Out, Optional] IntPtr lpOutBuffer, [In, Optional] uint nOutBufferSize,
		out uint lpBytesReturned, [In, Out, Optional] IntPtr lpOverlapped);

	/// <summary>
	/// Sends a control code directly to a specified device driver, causing the corresponding device to perform the corresponding operation.
	/// </summary>
	/// <param name="hDevice">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="dwIoControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <param name="lpInBuffer">
	/// A pointer to the input buffer that contains the data required to perform the operation. The format of this data depends on the
	/// value of the dwIoControlCode parameter.
	/// <para>This parameter can be NULL if dwIoControlCode specifies an operation that does not require input data.</para>
	/// </param>
	/// <param name="nInBufferSize">The size of the input buffer, in bytes.</param>
	/// <param name="lpOutBuffer">
	/// A pointer to the output buffer that is to receive the data returned by the operation. The format of this data depends on the
	/// value of the dwIoControlCode parameter.
	/// <para>This parameter can be NULL if dwIoControlCode specifies an operation that does not return data.</para>
	/// </param>
	/// <param name="nOutBufferSize">The size of the output buffer, in bytes.</param>
	/// <param name="lpBytesReturned">
	/// A pointer to a variable that receives the size of the data stored in the output buffer, in bytes.
	/// <para>
	/// If the output buffer is too small to receive any data, the call fails, GetLastError returns ERROR_INSUFFICIENT_BUFFER, and
	/// lpBytesReturned is zero.
	/// </para>
	/// <para>
	/// If the output buffer is too small to hold all of the data but can hold some entries, some drivers will return as much data as
	/// fits. In this case, the call fails, GetLastError returns ERROR_MORE_DATA, and lpBytesReturned indicates the amount of data
	/// received. Your application should call DeviceIoControl again with the same operation, specifying a new starting point.
	/// </para>
	/// <para>
	/// If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation returns no output data and lpOutBuffer is NULL,
	/// DeviceIoControl makes use of lpBytesReturned. After such an operation, the value of lpBytesReturned is meaningless.
	/// </para>
	/// <para>
	/// If lpOverlapped is not NULL, lpBytesReturned can be NULL. If this parameter is not NULL and the operation returns data,
	/// lpBytesReturned is meaningless until the overlapped operation has completed. To retrieve the number of bytes returned, call
	/// GetOverlappedResult. If hDevice is associated with an I/O completion port, you can retrieve the number of bytes returned by
	/// calling GetQueuedCompletionStatus.
	/// </para>
	/// </param>
	/// <param name="lpOverlapped">
	/// A pointer to an OVERLAPPED structure.
	/// <para>If hDevice was opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.</para>
	/// <para>
	/// If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, the operation is performed as an overlapped (asynchronous) operation.
	/// In this case, lpOverlapped must point to a valid OVERLAPPED structure that contains a handle to an event object. Otherwise, the
	/// function fails in unpredictable ways.
	/// </para>
	/// <para>
	/// For overlapped operations, DeviceIoControl returns immediately, and the event object is signaled when the operation has been
	/// completed. Otherwise, the function does not return until the operation has been completed or an error occurs.
	/// </para>
	/// </param>
	/// <returns>
	/// If the operation completes successfully, the return value is nonzero.
	/// <para>If the operation fails or is pending, the return value is zero. To get extended error information, call GetLastError.</para>
	/// </returns>
	/// <remarks>
	/// <para>
	/// To retrieve a handle to the device, you must call the CreateFile function with either the name of a device or the name of the
	/// driver associated with a device. To specify a device name, use the following format:
	/// </para>
	/// <para>\\.\DeviceName</para>
	/// <para>
	/// DeviceIoControl can accept a handle to a specific device. For example, to open a handle to the logical drive
	/// A: with CreateFile, specify \\.\a:. Alternatively, you can use the names \\.\PhysicalDrive0, \\.\PhysicalDrive1, and so on, to
	/// open handles to the physical drives on a system.
	/// </para>
	/// <para>
	/// You should specify the FILE_SHARE_READ and FILE_SHARE_WRITE access flags when calling CreateFile to open a handle to a device
	/// driver. However, when you open a communications resource, such as a serial port, you must specify exclusive access. Use the other
	/// CreateFile parameters as follows when opening a device handle:
	/// </para>
	/// <list type="bullet">
	/// <item>
	/// <description>The fdwCreate parameter must specify OPEN_EXISTING.</description>
	/// </item>
	/// <item>
	/// <description>The hTemplateFile parameter must be NULL.</description>
	/// </item>
	/// <item>
	/// <description>
	/// The fdwAttrsAndFlags parameter can specify FILE_FLAG_OVERLAPPED to indicate that the returned handle can be used in overlapped
	/// (asynchronous) I/O operations.
	/// </description>
	/// </item>
	/// </list>
	/// </remarks>
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static extern unsafe bool DeviceIoControl(HFILE hDevice, uint dwIoControlCode, [In, Optional] byte* lpInBuffer,
		[In, Optional] uint nInBufferSize, [Out, Optional] byte* lpOutBuffer, [In, Optional] uint nOutBufferSize,
		out uint lpBytesReturned, [In, Out, Optional] NativeOverlapped* lpOverlapped);

	/// <summary>
	/// Sends a control code directly to a specified device driver, causing the corresponding device to perform the corresponding operation.
	/// </summary>
	/// <param name="hDev">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="ioControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <returns><c>true</c> if successful.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static bool DeviceIoControl(HFILE hDev, uint ioControlCode) =>
		DeviceIoControl(hDev, ioControlCode, IntPtr.Zero, 0, IntPtr.Zero, 0, out _, IntPtr.Zero);

	/// <summary>
	/// Sends a control code directly to a specified device driver, causing the corresponding device to perform the corresponding operation.
	/// </summary>
	/// <typeparam name="TIn">The type of the <paramref name="inVal"/>.</typeparam>
	/// <typeparam name="TOut">The type of the <paramref name="outVal"/>.</typeparam>
	/// <param name="hDev">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream. To
	/// retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="ioControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which to
	/// perform it.
	/// </param>
	/// <param name="inVal">
	/// The data required to perform the operation. The format of this data depends on the value of the dwIoControlCode parameter.
	/// </param>
	/// <param name="outVal">The data returned by the operation. The format of this data depends on the value of the dwIoControlCode parameter.</param>
	/// <param name="outSz">
	/// The amount of memory to allocate for <paramref name="outVal"/> retrieval. If this value is <c>0</c>, then initialize the default structure.
	/// </param>
	/// <returns><c>true</c> if successful.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static bool DeviceIoControl<TIn, TOut>(HFILE hDev, uint ioControlCode, TIn inVal, out TOut outVal, SizeT outSz = default) where TIn : struct where TOut : struct
	{
		using SafeHGlobalHandle ptrIn = SafeHGlobalHandle.CreateFromStructure(inVal), ptrOut = outSz == 0 ? SafeHGlobalHandle.CreateFromStructure<TOut>() : new(outSz);
		var ret = DeviceIoControl(hDev, ioControlCode, ptrIn, ptrIn.Size, ptrOut, ptrOut.Size, out var bRet, IntPtr.Zero);
		if (!ret && Win32Error.GetLastError() == Win32Error.ERROR_INSUFFICIENT_BUFFER)
		{
			ptrOut.Size = bRet == 0 ? ptrOut.Size * 16 : bRet;
			ret = DeviceIoControl(hDev, ioControlCode, ptrIn, ptrIn.Size, ptrOut, ptrOut.Size, out bRet, IntPtr.Zero);
		}
		outVal = ret ? ptrOut.ToStructure<TOut>() : default;
		return ret;
	}

	/// <summary>
	/// Sends a control code directly to a specified device driver, causing the corresponding device to perform the corresponding operation.
	/// </summary>
	/// <typeparam name="TOut">The type of the <paramref name="outVal"/>.</typeparam>
	/// <param name="hDev">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="ioControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <param name="outVal">
	/// The data returned by the operation. The format of this data depends on the value of the dwIoControlCode parameter.
	/// </param>
	/// <param name="outSz">
	/// The amount of memory to allocate for <paramref name="outVal"/> retrieval. If this value is <c>0</c>, then initialize the default structure.
	/// </param>
	/// <returns><c>true</c> if successful.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static bool DeviceIoControl<TOut>(HFILE hDev, uint ioControlCode, out TOut outVal, SizeT outSz = default) where TOut : struct
	{
		using var ptrOut = outSz == 0 ? SafeHGlobalHandle.CreateFromStructure<TOut>() : new(outSz);
		var ret = DeviceIoControl(hDev, ioControlCode, IntPtr.Zero, 0, ptrOut, ptrOut.Size, out var bRet, IntPtr.Zero);
		var err = Win32Error.GetLastError();
		if (!ret && err == Win32Error.ERROR_INSUFFICIENT_BUFFER)
		{
			ptrOut.Size = bRet == 0 ? ptrOut.Size * 16 : bRet;
			ret = DeviceIoControl(hDev, ioControlCode, IntPtr.Zero, 0, ptrOut, ptrOut.Size, out bRet, IntPtr.Zero);
#if DEBUG
			err = Win32Error.GetLastError();
#endif
		}
		outVal = ret ? ptrOut.ToStructure<TOut>() : default;
		return ret;
	}

	/// <summary>
	/// Sends a control code directly to a specified device driver, causing the corresponding device to perform the corresponding operation.
	/// </summary>
	/// <typeparam name="TIn">The type of the <paramref name="inVal"/>.</typeparam>
	/// <param name="hDev">
	/// A handle to the device on which the operation is to be performed. The device is typically a volume, directory, file, or stream.
	/// To retrieve a device handle, use the CreateFile function. For more information, see Remarks.
	/// </param>
	/// <param name="ioControlCode">
	/// The control code for the operation. This value identifies the specific operation to be performed and the type of device on which
	/// to perform it.
	/// </param>
	/// <param name="inVal">
	/// The data required to perform the operation. The format of this data depends on the value of the dwIoControlCode parameter.
	/// </param>
	/// <returns><c>true</c> if successful.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static bool DeviceIoControl<TIn>(HFILE hDev, uint ioControlCode, TIn inVal) where TIn : struct
	{
		using var ptrIn = SafeHGlobalHandle.CreateFromStructure(inVal);
		return DeviceIoControl(hDev, ioControlCode, ptrIn, ptrIn.Size, IntPtr.Zero, 0, out _, IntPtr.Zero);
	}

	/// <summary>Ends the asynchronous call to <c>BeginDeviceIoControl&lt;TIn, TOut&gt;(HFILE, uint, TIn?, TOut?, AsyncCallback)</c>.</summary>
	/// <typeparam name="TIn">The type of the input value.</typeparam>
	/// <typeparam name="TOut">The type of the output value.</typeparam>
	/// <param name="asyncResult">The asynchronous result returned from <c>BeginDeviceIoControl&gt;TIn, TOut&lt;(HFILE, uint, TIn?, TOut?, AsyncCallback)</c>.</param>
	/// <returns>The output value, if exists; <c>null</c> otherwise.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static TOut? EndDeviceIoControl<TIn, TOut>(IAsyncResult asyncResult) where TIn : struct where TOut : struct
	{
		var ret = OverlappedAsync.EndOverlappedFunction(asyncResult);
		return Unpack<TIn, TOut>((byte[]?)ret).Item2;
	}

	/// <summary>Ends the asynchronous call to <c>BeginDeviceIoControl&lt;TIn, TOut&gt;(HFILE, uint, TIn?, TOut?, AsyncCallback)</c>.</summary>
	/// <param name="asyncResult">
	/// The asynchronous result returned from <c>BeginDeviceIoControl&lt;TIn, TOut&gt;(HFILE, uint, TIn?, TOut?, AsyncCallback)</c>.
	/// </param>
	/// <returns>The output buffer, if exists; <c>null</c> otherwise.</returns>
	[PInvokeData("Winbase.h", MSDNShortId = "aa363216")]
	public static byte[]? EndDeviceIoControl(IAsyncResult asyncResult)
	{
		var ret = OverlappedAsync.EndOverlappedFunction(asyncResult);
		return Unpack((byte[]?)ret).Item2;
	}

	/// <summary>
	/// Retrieves the results of an overlapped operation on the specified file, named pipe, or communications device. To specify a
	/// timeout interval or wait on an alertable thread, use <c>GetOverlappedResultEx</c>.
	/// </summary>
	/// <param name="hFile">
	/// A handle to the file, named pipe, or communications device. This is the same handle that was specified when the overlapped
	/// operation was started by a call to the <c>ReadFile</c>, <c>WriteFile</c>, <c>ConnectNamedPipe</c>, <c>TransactNamedPipe</c>,
	/// <c>DeviceIoControl</c>, or <c>WaitCommEvent</c> function.
	/// </param>
	/// <param name="lpOverlapped">
	/// A pointer to an <c>OVERLAPPED</c> structure that was specified when the overlapped operation was started.
	/// </param>
	/// <param name="lpNumberOfBytesTransferred">
	/// A pointer to a variable that receives the number of bytes that were actually transferred by a read or write operation. For a
	/// <c>TransactNamedPipe</c> operation, this is the number of bytes that were read from the pipe. For a <c>DeviceIoControl</c>
	/// operation, this is the number of bytes of output data returned by the device driver. For a <c>ConnectNamedPipe</c> or
	/// <c>WaitCommEvent</c> operation, this value is undefined.
	/// </param>
	/// <param name="bWait">
	/// If this parameter is <c>TRUE</c>, and the <c>Internal</c> member of the lpOverlapped structure is <c>STATUS_PENDING</c>, the
	/// function does not return until the operation has been completed. If this parameter is <c>FALSE</c> and the operation is still
	/// pending, the function returns <c>FALSE</c> and the <c>GetLastError</c> function returns <c>ERROR_IO_INCOMPLETE</c>.
	/// </param>
	/// <returns>
	/// <para>If the function succeeds, the return value is nonzero.</para>
	/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
	/// </returns>
	// BOOL WINAPI GetOverlappedResult( _In_ HANDLE hFile, _In_ LPOVERLAPPED lpOverlapped, _Out_ LPDWORD lpNumberOfBytesTransferred, _In_
	// BOOL bWait); https://msdn.microsoft.com/en-us/library/windows/desktop/ms683209(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("WinBase.h", MSDNShortId = "ms683209")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern unsafe bool GetOverlappedResult([In] HFILE hFile, [In] NativeOverlapped* lpOverlapped, out uint lpNumberOfBytesTransferred, [MarshalAs(UnmanagedType.Bool)] bool bWait);

	/// <summary>
	/// Retrieves the results of an overlapped operation on the specified file, named pipe, or communications device within the specified
	/// time-out interval. The calling thread can perform an alertable wait.
	/// </summary>
	/// <param name="hFile">
	/// A handle to the file, named pipe, or communications device. This is the same handle that was specified when the overlapped
	/// operation was started by a call to the <c>ReadFile</c>, <c>WriteFile</c>, <c>ConnectNamedPipe</c>, <c>TransactNamedPipe</c>,
	/// <c>DeviceIoControl</c>, or <c>WaitCommEvent</c> function.
	/// </param>
	/// <param name="lpOverlapped">
	/// A pointer to an <c>OVERLAPPED</c> structure that was specified when the overlapped operation was started.
	/// </param>
	/// <param name="lpNumberOfBytesTransferred">
	/// A pointer to a variable that receives the number of bytes that were actually transferred by a read or write operation. For a
	/// <c>TransactNamedPipe</c> operation, this is the number of bytes that were read from the pipe. For a <c>DeviceIoControl</c>
	/// operation, this is the number of bytes of output data returned by the device driver. For a <c>ConnectNamedPipe</c> or
	/// <c>WaitCommEvent</c> operation, this value is undefined.
	/// </param>
	/// <param name="dwMilliseconds">
	/// <para>The time-out interval, in milliseconds.</para>
	/// <para>
	/// If dwMilliseconds is zero and the operation is still in progress, the function returns immediately and the <c>GetLastError</c>
	/// function returns <c>ERROR_IO_INCOMPLETE</c>.
	/// </para>
	/// <para>
	/// If dwMilliseconds is nonzero and the operation is still in progress, the function waits until the object is signaled, an I/O
	/// completion routine or APC is queued, or the interval elapses before returning. Use <c>GetLastError</c> to get extended error information.
	/// </para>
	/// <para>
	/// If dwMilliseconds is <c>INFINITE</c>, the function returns only when the object is signaled or an I/O completion routine or APC
	/// is queued.
	/// </para>
	/// </param>
	/// <param name="bAlertable">
	/// <para>
	/// If this parameter is <c>TRUE</c> and the calling thread is in the waiting state, the function returns when the system queues an
	/// I/O completion routine or APC. The calling thread then runs the routine or function. Otherwise, the function does not return, and
	/// the completion routine or APC function is not executed.
	/// </para>
	/// <para>
	/// A completion routine is queued when the <c>ReadFileEx</c> or <c>WriteFileEx</c> function in which it was specified has completed.
	/// The function returns and the completion routine is called only if bAlertable is <c>TRUE</c>, and the calling thread is the thread
	/// that initiated the read or write operation. An APC is queued when you call <c>QueueUserAPC</c>.
	/// </para>
	/// </param>
	/// <returns>
	/// <para>If the function succeeds, the return value is nonzero.</para>
	/// <para>
	/// If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>. Common error codes
	/// include the following:
	/// </para>
	/// </returns>
	// WINBASEAPI BOOL WINAPI GetOverlappedResultEx( _In_ HANDLE hFile, _In_ LPOVERLAPPED lpOverlapped, _Out_ LPDWORD
	// lpNumberOfBytesTransferred, _In_ DWORD dwMilliseconds, _In_ BOOL bAlertable); https://msdn.microsoft.com/en-us/library/windows/desktop/hh448542(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("Ioapiset.h", MSDNShortId = "hh448542")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern unsafe bool GetOverlappedResultEx([In] HFILE hFile, [In] NativeOverlapped* lpOverlapped, out uint lpNumberOfBytesTransferred, uint dwMilliseconds, [MarshalAs(UnmanagedType.Bool)] bool bAlertable);

	/// <summary>
	/// <para>
	/// Attempts to dequeue an I/O completion packet from the specified I/O completion port. If there is no completion packet queued, the
	/// function waits for a pending I/O operation associated with the completion port to complete.
	/// </para>
	/// <para>To dequeue multiple I/O completion packets at once, use the <c>GetQueuedCompletionStatusEx</c> function.</para>
	/// </summary>
	/// <param name="CompletionPort">
	/// A handle to the completion port. To create a completion port, use the <c>CreateIoCompletionPort</c> function.
	/// </param>
	/// <param name="lpNumberOfBytes">
	/// A pointer to a variable that receives the number of bytes transferred during an I/O operation that has completed.
	/// </param>
	/// <param name="lpCompletionKey">
	/// A pointer to a variable that receives the completion key value associated with the file handle whose I/O operation has completed.
	/// A completion key is a per-file key that is specified in a call to <c>CreateIoCompletionPort</c>.
	/// </param>
	/// <param name="lpOverlapped">
	/// <para>
	/// A pointer to a variable that receives the address of the <c>OVERLAPPED</c> structure that was specified when the completed I/O
	/// operation was started.
	/// </para>
	/// <para>
	/// Even if you have passed the function a file handle associated with a completion port and a valid <c>OVERLAPPED</c> structure, an
	/// application can prevent completion port notification. This is done by specifying a valid event handle for the <c>hEvent</c>
	/// member of the <c>OVERLAPPED</c> structure, and setting its low-order bit. A valid event handle whose low-order bit is set keeps
	/// I/O completion from being queued to the completion port.
	/// </para>
	/// </param>
	/// <param name="dwMilliseconds">
	/// <para>
	/// The number of milliseconds that the caller is willing to wait for a completion packet to appear at the completion port. If a
	/// completion packet does not appear within the specified time, the function times out, returns <c>FALSE</c>, and sets *lpOverlapped
	/// to <c>NULL</c>.
	/// </para>
	/// <para>
	/// If dwMilliseconds is <c>INFINITE</c>, the function will never time out. If dwMilliseconds is zero and there is no I/O operation
	/// to dequeue, the function will time out immediately.
	/// </para>
	/// </param>
	/// <returns>
	/// <para>Returns nonzero ( <c>TRUE</c>) if successful or zero ( <c>FALSE</c>) otherwise.</para>
	/// <para>To get extended error information, call <c>GetLastError</c>.</para>
	/// <para>For more information, see the Remarks section.</para>
	/// </returns>
	// BOOL WINAPI GetQueuedCompletionStatus( _In_ HANDLE CompletionPort, _Out_ LPDWORD lpNumberOfBytes, _Out_ PULONG_PTR
	// lpCompletionKey, _Out_ LPOVERLAPPED
	// *lpOverlapped, _In_ DWORD dwMilliseconds); https://msdn.microsoft.com/en-us/library/windows/desktop/aa364986(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("WinBase.h", MSDNShortId = "aa364986")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern unsafe bool GetQueuedCompletionStatus([In] HANDLE CompletionPort, out uint lpNumberOfBytes, out IntPtr lpCompletionKey, NativeOverlapped** lpOverlapped, uint dwMilliseconds);

	/// <summary>
	/// <para>
	/// Attempts to dequeue an I/O completion packet from the specified I/O completion port. If there is no completion packet queued, the
	/// function waits for a pending I/O operation associated with the completion port to complete.
	/// </para>
	/// <para>To dequeue multiple I/O completion packets at once, use the <c>GetQueuedCompletionStatusEx</c> function.</para>
	/// </summary>
	/// <param name="CompletionPort">
	/// A handle to the completion port. To create a completion port, use the <c>CreateIoCompletionPort</c> function.
	/// </param>
	/// <param name="lpNumberOfBytes">
	/// A pointer to a variable that receives the number of bytes transferred during an I/O operation that has completed.
	/// </param>
	/// <param name="lpCompletionKey">
	/// A pointer to a variable that receives the completion key value associated with the file handle whose I/O operation has completed.
	/// A completion key is a per-file key that is specified in a call to <c>CreateIoCompletionPort</c>.
	/// </param>
	/// <param name="lpOverlapped">
	/// <para>
	/// A pointer to a variable that receives the address of the <c>OVERLAPPED</c> structure that was specified when the completed I/O
	/// operation was started.
	/// </para>
	/// <para>
	/// Even if you have passed the function a file handle associated with a completion port and a valid <c>OVERLAPPED</c> structure, an
	/// application can prevent completion port notification. This is done by specifying a valid event handle for the <c>hEvent</c>
	/// member of the <c>OVERLAPPED</c> structure, and setting its low-order bit. A valid event handle whose low-order bit is set keeps
	/// I/O completion from being queued to the completion port.
	/// </para>
	/// </param>
	/// <param name="dwMilliseconds">
	/// <para>
	/// The number of milliseconds that the caller is willing to wait for a completion packet to appear at the completion port. If a
	/// completion packet does not appear within the specified time, the function times out, returns <c>FALSE</c>, and sets *lpOverlapped
	/// to <c>NULL</c>.
	/// </para>
	/// <para>
	/// If dwMilliseconds is <c>INFINITE</c>, the function will never time out. If dwMilliseconds is zero and there is no I/O operation
	/// to dequeue, the function will time out immediately.
	/// </para>
	/// </param>
	/// <returns>
	/// <para>Returns nonzero ( <c>TRUE</c>) if successful or zero ( <c>FALSE</c>) otherwise.</para>
	/// <para>To get extended error information, call <c>GetLastError</c>.</para>
	/// <para>For more information, see the Remarks section.</para>
	/// </returns>
	// BOOL WINAPI GetQueuedCompletionStatus( _In_ HANDLE CompletionPort, _Out_ LPDWORD lpNumberOfBytes, _Out_ PULONG_PTR
	// lpCompletionKey, _Out_ LPOVERLAPPED
	// *lpOverlapped, _In_ DWORD dwMilliseconds); https://msdn.microsoft.com/en-us/library/windows/desktop/aa364986(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("WinBase.h", MSDNShortId = "aa364986")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern bool GetQueuedCompletionStatus([In] HANDLE CompletionPort, out uint lpNumberOfBytes, out IntPtr lpCompletionKey, out IntPtr lpOverlapped, uint dwMilliseconds);

	/// <summary>
	/// <para>
	/// Retrieves multiple completion port entries simultaneously. It waits for pending I/O operations that are associated with the
	/// specified completion port to complete.
	/// </para>
	/// <para>To dequeue I/O completion packets one at a time, use the <c>GetQueuedCompletionStatus</c> function.</para>
	/// </summary>
	/// <param name="CompletionPort">
	/// A handle to the completion port. To create a completion port, use the <c>CreateIoCompletionPort</c> function.
	/// </param>
	/// <param name="lpCompletionPortEntries">
	/// <para>On input, points to a pre-allocated array of <c>OVERLAPPED_ENTRY</c> structures.</para>
	/// <para>
	/// On output, receives an array of <c>OVERLAPPED_ENTRY</c> structures that hold the entries. The number of array elements is
	/// provided by ulNumEntriesRemoved.
	/// </para>
	/// <para>
	/// The number of bytes transferred during each I/O, the completion key that indicates on which file each I/O occurred, and the
	/// overlapped structure address used in each original I/O are all returned in the lpCompletionPortEntries array.
	/// </para>
	/// </param>
	/// <param name="ulCount">The maximum number of entries to remove.</param>
	/// <param name="ulNumEntriesRemoved">A pointer to a variable that receives the number of entries actually removed.</param>
	/// <param name="dwMilliseconds">
	/// <para>
	/// The number of milliseconds that the caller is willing to wait for a completion packet to appear at the completion port. If a
	/// completion packet does not appear within the specified time, the function times out and returns <c>FALSE</c>.
	/// </para>
	/// <para>
	/// If dwMilliseconds is <c>INFINITE</c> (0xFFFFFFFF), the function will never time out. If dwMilliseconds is zero and there is no
	/// I/O operation to dequeue, the function will time out immediately.
	/// </para>
	/// </param>
	/// <param name="fAlertable">
	/// <para>If this parameter is <c>FALSE</c>, the function does not return until the time-out period has elapsed or an entry is retrieved.</para>
	/// <para>
	/// If the parameter is <c>TRUE</c> and there are no available entries, the function performs an alertable wait. The thread returns
	/// when the system queues an I/O completion routine or APC to the thread and the thread executes the function.
	/// </para>
	/// <para>
	/// A completion routine is queued when the <c>ReadFileEx</c> or <c>WriteFileEx</c> function in which it was specified has completed,
	/// and the calling thread is the thread that initiated the operation. An APC is queued when you call <c>QueueUserAPC</c>.
	/// </para>
	/// </param>
	// BOOL WINAPI GetQueuedCompletionStatusEx( _In_ HANDLE CompletionPort, _Out_ LPOVERLAPPED_ENTRY lpCompletionPortEntries, _In_ ULONG
	// ulCount, _Out_ PULONG ulNumEntriesRemoved, _In_ DWORD dwMilliseconds, _In_ BOOL fAlertable); https://msdn.microsoft.com/en-us/library/windows/desktop/aa364988(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "aa364988")]
	public static extern void GetQueuedCompletionStatusEx(HANDLE CompletionPort, OVERLAPPED_ENTRY[] lpCompletionPortEntries, uint ulCount, out uint ulNumEntriesRemoved, uint dwMilliseconds, [MarshalAs(UnmanagedType.Bool)] bool fAlertable);

	/// <summary>Posts an I/O completion packet to an I/O completion port.</summary>
	/// <param name="CompletionPort">A handle to an I/O completion port to which the I/O completion packet is to be posted.</param>
	/// <param name="dwNumberOfBytesTransferred">
	/// The value to be returned through the lpNumberOfBytesTransferred parameter of the <c>GetQueuedCompletionStatus</c> function.
	/// </param>
	/// <param name="dwCompletionKey">
	/// The value to be returned through the lpCompletionKey parameter of the <c>GetQueuedCompletionStatus</c> function.
	/// </param>
	/// <param name="lpOverlapped">
	/// The value to be returned through the lpOverlapped parameter of the <c>GetQueuedCompletionStatus</c> function.
	/// </param>
	/// <returns>
	/// <para>If the function succeeds, the return value is nonzero.</para>
	/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c> .</para>
	/// </returns>
	// BOOL WINAPI PostQueuedCompletionStatus( _In_ HANDLE CompletionPort, _In_ DWORD dwNumberOfBytesTransferred, _In_ ULONG_PTR
	// dwCompletionKey, _In_opt_ LPOVERLAPPED lpOverlapped); https://msdn.microsoft.com/en-us/library/windows/desktop/aa365458(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "aa365458")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern unsafe bool PostQueuedCompletionStatus([In] HANDLE CompletionPort, uint dwNumberOfBytesTransferred,
		IntPtr dwCompletionKey, [In, Optional] NativeOverlapped* lpOverlapped);

	/// <summary>Posts an I/O completion packet to an I/O completion port.</summary>
	/// <param name="CompletionPort">A handle to an I/O completion port to which the I/O completion packet is to be posted.</param>
	/// <param name="dwNumberOfBytesTransferred">
	/// The value to be returned through the lpNumberOfBytesTransferred parameter of the <c>GetQueuedCompletionStatus</c> function.
	/// </param>
	/// <param name="dwCompletionKey">
	/// The value to be returned through the lpCompletionKey parameter of the <c>GetQueuedCompletionStatus</c> function.
	/// </param>
	/// <param name="lpOverlapped">
	/// The value to be returned through the lpOverlapped parameter of the <c>GetQueuedCompletionStatus</c> function.
	/// </param>
	/// <returns>
	/// <para>If the function succeeds, the return value is nonzero.</para>
	/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c> .</para>
	/// </returns>
	// BOOL WINAPI PostQueuedCompletionStatus( _In_ HANDLE CompletionPort, _In_ DWORD dwNumberOfBytesTransferred, _In_ ULONG_PTR
	// dwCompletionKey, _In_opt_ LPOVERLAPPED lpOverlapped); https://msdn.microsoft.com/en-us/library/windows/desktop/aa365458(v=vs.85).aspx
	[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
	[PInvokeData("IoAPI.h", MSDNShortId = "aa365458")]
	[return: MarshalAs(UnmanagedType.Bool)]
	public static extern bool PostQueuedCompletionStatus([In] HANDLE CompletionPort, uint dwNumberOfBytesTransferred,
		[In, Optional] IntPtr dwCompletionKey, [In, Optional] IntPtr lpOverlapped);

	private static unsafe IAsyncResult BeginDeviceIoControl<TIn, TOut>(HFILE hDevice, uint dwIoControlCode, byte[] buffer, AsyncCallback userCallback, object? userState) where TIn : struct where TOut : struct =>
		BeginDeviceIoControl(hDevice, dwIoControlCode, buffer, userCallback, userState);

	private static unsafe IAsyncResult BeginDeviceIoControl(HFILE hDevice, uint dwIoControlCode, byte[] buffer, AsyncCallback userCallback, object? userState)
	{
		var ar = OverlappedAsync.SetupOverlappedFunction(hDevice, userCallback, buffer);
		var intSz = Marshal.SizeOf<int>();
		var inSz = BitConverter.ToInt32(buffer, 0);
		var outSz = BitConverter.ToInt32(buffer, intSz);
		fixed (byte* pIn = &buffer[intSz * 2], pOut = &buffer[outSz == 0 ? 0 : intSz * 2 + inSz])
		{
			var ret = DeviceIoControl(hDevice, dwIoControlCode, pIn, (uint)inSz, pOut, (uint)outSz, out var bRet, ar.Overlapped);
			return OverlappedAsync.EvaluateOverlappedFunction(ar, ret);
		}
	}

	private static T MemRead<T>(byte[] buffer, ref int startIndex) where T : struct
	{
		using var pin = new PinnedObject(buffer, startIndex);
		startIndex += Marshal.SizeOf<T>();
		return ((IntPtr)pin).ToStructure<T>();
	}

	private static int MemWrite<T>(byte[] buffer, T value, int startIndex = 0) where T : struct
	{
		var sz = Marshal.SizeOf<T>();
		using (var pin = new PinnedObject(value))
			Marshal.Copy(pin, buffer, startIndex, sz);
		return sz;
	}

	private static byte[] Pack<TIn, TOut>(TIn? inVal, TOut? outVal) where TIn : struct where TOut : struct
	{
		using var ms = new MemoryStream();
		using var wtr = new BinaryWriter(ms);
		wtr.Write(inVal.HasValue ? Marshal.SizeOf<TIn>() : 0);
		wtr.Write(outVal.HasValue ? Marshal.SizeOf<TOut>() : 0);
		if (inVal.HasValue) wtr.Write(inVal.Value);
		if (outVal.HasValue) wtr.Write(outVal.Value);
		return ms.ToArray();
	}

	private static byte[] Pack(byte[]? inputBuffer, byte[]? outputBuffer)
	{
		using var ms = new MemoryStream();
		using var wtr = new BinaryWriter(ms);
		wtr.Write(inputBuffer?.Length ?? 0);
		wtr.Write(outputBuffer?.Length ?? 0);
		if (inputBuffer != null && inputBuffer.Length > 0)
			wtr.Write(inputBuffer);
		if (outputBuffer != null && outputBuffer.Length > 0)
			wtr.Write(outputBuffer);
		return ms.ToArray();
	}

	private static Tuple<TIn?, TOut?> Unpack<TIn, TOut>(byte[]? buffer) where TIn : struct where TOut : struct
	{
		if (buffer is null || buffer.Length == 0)
			return new Tuple<TIn?, TOut?>(null, null);
		using var ms = new MemoryStream(buffer);
		using var rdr = new BinaryReader(ms);
		var inLen = rdr.ReadInt32();
		var outLen = rdr.ReadInt32();
		return new Tuple<TIn?, TOut?>(inLen > 0 ? rdr.Read<TIn>() : (TIn?)null, outLen > 0 ? rdr.Read<TOut>() : (TOut?)null);
	}

	private static Tuple<byte[]?, byte[]?> Unpack(byte[]? buffer)
	{
		if (buffer is null || buffer.Length == 0)
			return new Tuple<byte[]?, byte[]?>(null, null);
		using var ms = new MemoryStream(buffer);
		using var rdr = new BinaryReader(ms);
		var inLen = rdr.ReadInt32();
		var outLen = rdr.ReadInt32();
		return new Tuple<byte[]?, byte[]?>(rdr.ReadBytes(inLen), rdr.ReadBytes(outLen));
	}

	/// <summary>Contains the information returned by a call to the GetQueuedCompletionStatusEx function.</summary>
	// https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-overlapped_entry typedef struct _OVERLAPPED_ENTRY {
	// ULONG_PTR lpCompletionKey; LPOVERLAPPED lpOverlapped; ULONG_PTR Internal; DWORD dwNumberOfBytesTransferred; } OVERLAPPED_ENTRY, *LPOVERLAPPED_ENTRY;
	[PInvokeData("minwinbase.h", MSDNShortId = "3e244e6c-0731-477a-b1d3-2601c29449ca")]
	[StructLayout(LayoutKind.Sequential)]
	public struct OVERLAPPED_ENTRY
	{
		/// <summary>
		/// Receives the completion key value associated with the file handle whose I/O operation has completed. A completion key is a
		/// per-file key that is specified in a call to CreateIoCompletionPort.
		/// </summary>
		public IntPtr lpCompletionKey;

		/// <summary>Receives the address of the OVERLAPPED structure that was specified when the completed I/O operation was started.</summary>
		public IntPtr lpOverlapped;

		/// <summary>Reserved.</summary>
		public UIntPtr Internal;

		/// <summary>Receives the number of bytes transferred during the I/O operation that has completed.</summary>
		public uint dwNumberOfBytesTransferred;
	}
}